Gas burner control system



A ril 12, 1932. J. c. BOGLE 7 1,853,195

GAS BURNER CONTROL SYSTEM Original Filed lviarch 21, 1927 0/- SUPPI. K

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50086: 0/- suPPL Y Mai/z 6 [fay/a2 Patented Apr; 12, 1932 UNITED STATES PATENT OFFICE JOHN C. BOGLE, 0]? RIVER FOREST, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, OF MINNEAPOLIS, MINNESOTA,

A. CORPORATION OF DELAWARE GAS BURNER CONTROL SYSTEM Original application Serial No. 176,859, filed March 21, 1927. Divided and this application filed December 11, 1928. Serial No. 325,171. 1

This application is a division of ,application Ser. No. 176,859 filed Mar. 21, 1927, for gas burner control system by the applicant of this application.

This invention relates to a control system for gas burners and has special reference to a safety control'system for a gas-fired boiler or other appliances or apparatus employing gas for its operation.

Hereinafter this inventinon will be illustrated and described in connection with an automatic heating system, although it is to be understood that this system may be employed wherever it is desirable to promote a substantially even temperature, to provide a periodic supply or demand, or any other instance wherein gas is permitted to flow to a burner at intervals.

Automatic heating systems are equipped with controls responsive to variations of temperature in a rooom or other enclosure to be heated. For example, such a control may comprise a wall thermostat capable of directing the generation of heat for assuring against substantial variations in the room temperature. Other forms of controls for automatic heating systems are those directing the specific limits of temperature to be obtained in the boiler or furnace. These lat- .ter instruments may include a water thermoable. In order to avoid complication of the drawings and disclosure, the several embodiments of this invention are primarily controlled by a simple room thermostat.

This invention is further enhanced by safety controls which operate to shut down the system in the event of failure of those controls previously recited to promote or sustain desirable conditions of combustion within the boiler or furnace.

Moreover, in order to illustrate the further usefulness of the control system, the invention has been incorporated in an automatic heating system wherein the burner is supplied with a mixture of gas and air under pressure.

. Other objects will be apparent from the description and the drawings forming a part of this specification, to which reference may now be had'for a more complete understanding of the characteristic features of this invention, in which drawings:

Figure 1 is a more or less diagrammatic view of a gas burner control system;

Fig. 2 is a view similar to Fig. 1 showing another form of gas control system; and

Fig. 3 is a vertical sectional view of the ignition device incorporated in the above control system.

Referring now to the drawings, and more particularly to Fig. 1 thereof, the control system comprises a reducing valve 10 which is directly connected to the main supply of gas 11. It is usual for gas to be supplied for domestic use at about six to eight ounces of pressure. The reducing valve 10 reduces this line pressure to any desired pressure, in this instance to about two ounces, which latter pressure is substantially constant. The gas under reduced pressure is directed to the lower chamber of arelay or snap valve 12 through a conduit 13, and thence to the main burner 14 through a conduit 15. In order to automatically control the supply of gas to the main burner so that the room temperature will remain substantially constant, some of the gas from the reducing valve 10 is by passed to the upper chamber of the snap valve 12 through conduits 16, 17 and 18, a throttling valve 19 being positioned between conduits 16 and'17. A magnetic valve 20 is connected to a T-fitting through conduit 21 and therefore communicates with conduits 17 and 18.

The devices of the control system will now be specifically described, whereafter their operation in the system will be related. The

reducing valve 10 is 'of the usual type having upper and lower chambers separated by means of a diaphragm 22, said diaphragm having a valve 23 secured thereto and extending into the lower chamber and seatingin a suitable valve seat 24. An adjustable screw 25 is prbvided in the upper chamber for asserting a proper pressure upon the diaphragm 22 so that any desired pressure of gas may be obtained within the lower chamber. lt'is desirable, although not essential to the operation of this system, to provide such a re formed in the opposite side and below said inlet port. A main port 28 connects the inlet and outlet openings, the port 28 being controlled by the movement of an iron plunger 29 which is vertically reciprocable in an upstanding tubular member 30 which latter is suitably secured to the metal base member 26 and rises substantially centrally therefrom. A spring 31 is secured between the top of the tubular portion 30 and the upper end of the plunger 29 whereby the plunger is maintained in position to close the main port 28 when the valve is de-energized. -The tubular portion 30 comprises an electromagnetic coil of the usual construction. In the operation of this device the coil is energized and the electromagnetic lines thread through the plunger 29 and the latter is raised against the action of the spring 31, whereby the degree of opening of the main port 28 is controlled.

A more complete understanding of the construction and operation of this device may be had by reference to a co'pendin g application filed November 27, 1925, bearing Serial No. 71,860.

The magnetic valve 20 is electrically connected to a room thermostatically operated switch 32 which controls the energization and de-energization of the electromagnetic coil 30. This room switch 32 may be of any usual type but for the purpose of a specific illustration and means for a better understanding, the device has been shown in the drawings as comprising'a mounting base of a suita le insulating material to which is secured a bracket 33 having a downwardly extending portion 34. A thermostatic element 35 of an expansible and contractiblc bellows type is supported by an extension 36 mounted on the insulating base. The other side of the bellows contacts with an actuating arm member 37 which latter occupies a substantially vertical position and is pivoted at its lower end to the insulating base. The upper end of the arm 37 is adjust-ably connected by means of a link 38 to the downwardly extending portion 34, which portion suitably supports a mercury contactor tube 39 of the usual type having a body of mercury and a pair of spaced cooperating electrodes disposed therein.

The bracket is tiltably mounted on the insulating base and is actuated into its various positions by means of the bellows 35 which latter is provided with a highly volatile fluid, thus rendering the bellows sensitive to the slightest temperature change. The bellows 35 either contract or expand to move arm 37 \Vl1lCl1,'l)OlIlg linked to the extension 31, causes the mercury tube 39 to tilt in positions whereby the n'iercurycontactor will be caused either to bridge the electrodes and to close the electrical circuit therethrough, or to flow in the opposite direction wherein the electrical circuit is opened.

For a better understanding of the elements of this device and the operation of the same, reference may be had to a co-pending application, Serial No. 7 39,006, filed Sept. 22, 1921, and assigned to my assignee.

The relay or snap valve 12 comprises upper and lower chambers separated by means of a diaphragm 40, the diaphragm in turn having mounted thereon a valve 11 for engagement with a valve seat provided in the inlet for the conduit 13 in the lower chamber. In the operation of this snap valve 12, when the desired pressure is obtained in the upper chamber, this pressure will force the diaphragm 40 to seat the valve 11 and shut oit the supply of gas through the lower chamber to the burner. \Vhen there is no pressure 111 the upper chamber or the pressure is substantially reduced, the diaphragm 40 136111111:

the valve member 41 to unseat, thereby permitting a flow of gas from the conduit 13 through the lower chamber and thence through the conduit 15 to the burner 14.

In the operation of the system thus far described, when the room in which the thermo I statically controlled device 32 is positioned,

has reached a desiredtemperature, the change in temperature will cause the bellows 35 to tilt the cont-actor tube 39 to a position wherein the mercury will bridge the electrodes and close an electrical circuit there- 33 through which in turn will cause the plunger 29 of the magnetic valve 20 to rise and to permit a flow of gas therethrough and through conduit 27. The magnetic valve 20 is so constructed that more gas is capable of passing therethrough when the same open than can escape through the throttling valve 19. lVhen the magnetic valve is closed the gas escaping through the throttling valve 19 builds up a pressure in the upper chamber of the snap valve 12; therefore, when the circuit through the contactor 39 is open and no current is passing through the coil of the electromagneticvalve 20, the plunger 29 is in its lowered position, closing the main port A i 28, whereby a pressure built up in the 11 per chamber of the snap valve 12 to close the determined temperature, the contactor 39 is tilted to a position such that an electrical circuit exists therethrough to energize the coil of the electromagnet whereby the iron plunger is raised to permit the escape of gas through the by-pass and from the upper chamber of the snapvalve 12, whereby the pressure in the upper chamber is relieved and the valve 41 is opened to permit a supply of gas to the burner 14. The gas from the electromagnetic valve 20 is passed through the conduit 27 to a safety pilot 42 which safety pilot will now be described.

The safety pilot 42 comprises an elongated '4 tubular member 43 having an aperture 44 at its upper end through which gas is permitted to escape in order to ignite the main burner 14. Gas is supplied through conduit 45 to the lower portion of the tubular member 43, said tubular member being of a relatively high coefficient of expansion. A spring member 46 is suitably attached at one of'its ends to the tubular member 43 and is perforated to permit the tubular member 43 to pass therethrough. The spring member 46 extends at substantially right angles to the tubular member and has secured at its outer end a valve stem 47, which latter projects downwardly through a packing gland to a point adjacent a seat 48 in a valve housing 49. The valve stem 47 has a lower coefficient of expansion than that of the tubular member 43. The conduit 27, which extends from the magnetic valve 20, is connected to the valve 49 at a point below the seat 48. A conduit 50 is connected to the valve housing 49 at a point above the seat 48 and communicates with the port provided between the packing gland and the seat 48, said conduit 50 extending upwardly and adjacent to the main burner 14 where gas emitted therefrom is ignited by said burner. 1

In the operation of the safety pilot the valve stem 47 is'normally open as the pilot light 44 is. constantly ignited. Heat proceeding from the flame, which emerges from the pilot'port, will cause the tubular member 43 to expand more than the valve stem. thereby providing a spaced relation between it and its seat; however, should the pilot light be extinguished, the tubular member 43 will contract faster and to a greater degree than the valve stem 47 thereby causing the latter to seat and shut off the supply of gas through the conduit 27 In the operation of this system, when the room in which the thermostatically controlled switch 32 is positioned has cooled, the electromagnetic valve 20 is caused to open, thereby relieving the pressure in'the top chamber of the snap valve 12 andpermittin g gas from the reducing valve 10 topass through to the burner 14. When a desired temperature has been obtained in the room in which the switch 32 is positioned, the switch automatically closes the magnetic valve 20, thus directing the by-passed gas downwardly through'con duit-18 and building up'a 'pressure in the upper chamber of the valve 12, which causes the valve in the lower chamber .to seat and ;v shut off the supply of gas from the reducing valve 10 to the burner '14.

When throttling valve 19 and the magnetic valve 20 is open, this gas passes through the conduit 27, the valve 49 and the extension 50 to be ignited by the burner 14. However, when gas isby-passed through the the magnetic valve 20 is closed, the by-passed gas then passes directly to the upper chamber of the snap valve 12. Should the thermostatic switch 32 be in a position such that the magnetic valve 20 is open permitting of a supply of gas to the burner 14, and should the pilot light 42 not be ignited, the valve stem 47 closes the passage-way through the valve 49 and causes a pressure to be built up in the upperchamber of the snap valve 12 to shut oil the supply of gas from the reducing valve 10 to the burner 14. It is apparent,-therefore, that the valve 49 and the magnetic valve 20 act in a similar manner to perform the same function.

Referring now to Fig.2 of the drawings, a

further modification of the same idea as involved in Fig. 1 is found. Gas is supplied to the reducing valve 51 from the main supply and passes therefrom through conduit 52 to the lower chamber of the snap valve 53 andfrom thence through conduit 54 to the burner 55. A portion of the gas from the reducing valve 51 is by-passed through the conduits 56, 57, and 58 to the upper chamber of the snap valve 53. In place of the magnetic valve, as described in the previous figures, a two-way magnetic valve 59 is shown comprising a twopart body portion 60 and 61 having a central opening 62 in which is disposed a valve head 63 mounted on an iron plunger 64 slidable vertically in a central core portion of the upper body portion 60. The conduit 56 is connected to the upper body portion and communicates with the central core portion thereof, and the conduit 57 is connected to the port 65, the junction between said central open- 'Cil Ilil

fore, that my invention be limited only by mostat 69 have thesame construction and have similar functions to the corresponding elements in the previously described figures.

In the operation of this device, when the' room in which the thermostatic switch 69 is disposed has cooled to a predetermined degree, an electrical circuit is completed therethrough whichenergizes the coil of the magnetic valve 59 and causes the plunger (i l to rise to its upper position, wherein communication between conduits 56 and 57 is shut off through the valve 59, although communication is established through the conduits by the medium of a throttling. valve 70 disposed in a by-pass conduit 71 between said conduits 56 and 58. The quantity of gas passing through the valve 70 is of a mag'ntiude much smaller than that which is permitted to pass through the valve 67 to be burned by the burner 55, thereby permitting escape of the gas. and preventing pressure from being. built up in the upper chamber of the snap valve 53 or relieving any pressure which has been built up therein. This action allows gas from the reducing valve 51 to pass through conduits 52 and 54 to the burner.

\Vhen a desired temperature has been obtainedin the room, the circuit is broken through the switch 69 which causes a de-cnergization of the magnetic coil in the valve 59 thereby releasing the plunger 60 which latter is. caused to seat and to shut oil the passage of the gas from the conduit 56 to the conduit 66. The gas from the conduit 56 now passes through the central opening of the upper body ortion 60' and through the con-, duit58 to tie upper chamber of the snap The safety pilot operates-the same in this modification as has been described in its operation in Fig. 1, the conduit 66 being closed whereby the gas '18 forced 1nto the upper" sure responsive means in the operation therechamber of the snap valve 53 to shut off the supply. of gas to the burner when the pilot light'does not function normally. v

lVhile I have described but two embodi ments of my invention, it is obvious that many modifications therein may occur to those skilled inthe art, and I desire, therethe-scope of the appended claims andby the prior art. 4

' I claim:

1. A control system for gas burners comprising a valve having chambers therein, one of said chambers being connected to said gas burner and being supplied with gas from the main supply, a valve for'controlling a sup ply of gas to the other. of said chambers whereby when said valve is operated into one position a pressure is built up in said latter chamber to shut oflt' the supply oflas from said burner and having a valve stem for engagement with said last mentioned valve whereby upon failure of the pilot to be ignited said latter valve is closed and a pressure is built up in said pressure chamber to shut off the supply. of gas from said first,

mentioned chamber to said humor.

2. A control system for gas burners comprising a main valve for controlling theflow of gas to a main burner and connected to a main source of supply, a gas actuated pressure device for operating said main valve, a valve for controlling the supply of gas to said device whereby when said valveis operated into one position a pressure is built up in said device to shutoff the supply of gas from said supply to the burner and when said valve is operated into the other position the pressure is relieved in said device to permit a flow of gas through the main valve to the burner, a valve for receiving-the gas bled from the pressure device, and a pilot for igniting said burner and having a valve stem for engagement with said last mentioned valve whereby on failure of the pilot to be'ignited said latter valve is closed and a pressure is built up in said pressure device to shut oil the supply of gas from said source to the main burner.

- 3. Apparatus for gas to a burner comprising a main valve, gas pressure responsive means for actuating the main valve, a control valve for regulating the flow of gas to and from said means, means formoving the. control valve in accordance 'with-. conditions resulting from the burning of the gas at the burner, and means for conducting the gas exhausted from said presof to the region of the burner for consumption at the same.

4. Apparatus for controlling the flow of gas. to aburner comprising amai'n valve, gas pressureresponsive means having a movable actuating element for actuating the main .valve, a three-Way valve for regulating the flow of gas to and from said element, means .for moving said three-way valve in accordcontrolling the flow of gas passage for supplying gas thereto, a diaphragm connected to the main gas valve and mounted on the casing so as to close the compartment and be actuated by the pressure 5 therein, a control Valve for regulating the flow of gas to and from the compartment so as to control the pressure therein, means for actuating said valve in accordance with conditions resulting from the consumption of 10 gas at the burner, and means for conducting the gas exhausted from said compartment to the region of the burner for consumption at the same.

In witness whereof, I have hereunto subscribed my name. JOHN G. BOGLE. 

